Greenland rises as ice cap melts

Emma Woollacott, 19th May 2010

It's not just sea levels that are rising as Greenland's ice melts - Greenland is too.

As its two-kilometer-thick ice cap melts, the pressure on the rock beneath decreases, potentially causing it to rise.

According to the University of Miami team, the uplift appears to have started in the late 90s. Some coastal areas are going up by nearly one inch per year.

If current trends continue, says the team, this will increase to as much as two inches per year by 2025.

Using specialized GPS receivers on the shores of Greenland, the scientists looked at data from 1995 onward. The raw GPS data were analyzed for high accuracy position information, as well as the vertical velocity and acceleration of each GPS site.

"It's been known for several years that climate change is contributing to the melting of Greenland's ice sheet," says professor of geophysics Tim Dixon.

"What's surprising, and a bit worrisome, is that the ice is melting so fast that we can actually see the land uplift in response. Even more surprising, the rise seems to be accelerating, implying that melting is accelerating."

The idea behind the study is that if Greenland is losing its ice cover, the resulting loss of weight causes the rocky surface beneath to rise. The same process is affecting the islands of Iceland and Svalbard, which also have ice caps, explains Shimon Wdowinski, research associate professor in the University of Miami RSMAS, and co-author of the study.

"During ice ages and in times of ice accumulation, the ice suppresses the land. When the ice melts, the land rebounds upwards," says co-author Shimon Wdowinski.

"Our study is consistent with a number of global warming indicators, confirming that ice melt and sea level rise are real and becoming significant."